1. Field of the Invention
The present invention relates to a stereoscopic endoscope system including left and right image pickup sections.
2. Description of the Related Art
In recent years, endoscopes have been widely used in a medical field and the like. A stereoscopic endoscope system using a stereoscopic endoscope is adopted in some cases to three-dimensionally observe a site to be operated or the like. In general, the stereoscopic endoscope includes a pair of left and right image pickup sections (or image pickup units). The left and right image pickup sections acquire parallax left and right pickup images of a subject (object), such as a site to be operated, and display the left and right images on a display apparatus through a signal processing apparatus. An operator uses polarization glasses or the like to three-dimensionally view the left and right images displayed on the display apparatus.
The left and right image pickup sections are set in a horizontally symmetrical state just after the manufacture of the stereoscopic endoscope and are set (adjusted) such that center positions of the left and right images respectively picked up by the left and right image pickup sections coincide to allow picking up images in a horizontally symmetrical image pickup state. However, degradation or the like of components included in the left and right image pickup sections due to repeated use generates a deviation from the horizontally symmetrical image pickup state, such as a deviation of the center positions.
Therefore, for example, Japanese Patent Application Laid-Open Publication No. 6-59196 discloses a configuration including adjustment means, in which a calibration tool as a reference of calibration is attached to a distal end portion of an insertion portion of a stereoscopic endoscope, reference images in which a distance from a distal end surface formed on an inner surface of the calibration tool is set to about several 10 mm are formed in left and right CCDs arranged at left and right image formation positions through left and right optical systems, respectively, and a relative position between the optical system and the CCDs is adjusted such that positions of images in the centers of fields of view in observation images picked up by the two CCDs coincide.